Research reveals the connection between high blood sugar and brain shrinkage

We’ve all heard about the myriad of health concerns surrounding sugar and high blood sugar levels. Maybe you’ve even heard that blood sugar can affect your brain. And it seems that the perils of high blood glucose truly do have a negative effect on the brain. New research has found that there is a connection between blood sugar levels and the size of the hippocampus — which is the region of the brain responsible for memory. In fact, a direct correlation between high blood sugar levels and shrinkage of the brain has been observed — as well as the memory, learning and cognitive difficulties to match.

New findings on the blood sugar-brain connection

A report from German researchers was recently published in the journal Neurology sought to further examine this phenomenon. To conduct their research, 141 human subjects with an average age of 63 were recruited to participate in their analysis. Their memory and learning capabilities were assessed, and the size of each individual’s hippocampus was measured using MRI brain scans. The participants’ blood sugar levels were also recorded.

The research team discovered that there was a direct correlation between lower blood glucose levels and positive results in several key areas of brain function. Better memory ability and a higher capacity to learn new things were both observed in those with lower blood sugar levels. There was also a significant relationship between blood sugar levels and hippocampus size: high blood sugar levels correlated with much more pronounced shrinkage of this valuable region of the brain.

Even individuals who didn’t have Type 2 diabetes or otherwise impaired glucose tolerance seemed to be susceptible to the ill effects of high blood sugar: brain health and overall well-being were still negatively affected by high blood glucose levels, even in the absence of these underlying health conditions. Their findings show just how important managing your blood sugar really is, and support similar findings from other researchers.

Evidence of high blood sugar’s adverse effects continues to mount

While glucose is essential for proper brain functioning because it is the brain’s preferred source of fuel, too much of it can yield some very much unwanted effects. Previous research published in 2012 by the journal Neurology found that even blood glucose levels on the high-end of what is considered normal could still be at a greater risk of brain shrinkage and diseases like dementia. While numerous studies had found that people with type 2 diabetes were at a greater risk for brain shrinkage and dementia, researchers wanted to know if other people could be at risk too.

Their findings also suggested that even people who do not have diabetes were still subject to adverse effects, even when their blood sugar was merely at the high end of “normal.”

In 2016, research published in the journal Cell found that high blood glucose levels had a serious impact, even at a cellular level. Karen N. Peart of Yale News writes, “[N]ot only do mitochondria of neurons ‘feel’ the change in circulating glucose levels, but that adaptive changes in these same mitochondria are at the core of the body’s ability to handle sugar in the blood.”

To put this theory to the test, researchers generated a number of animal models that either had a specific mitochondrial protein called uncoupling protein 2 (UCP2) in varying amounts in the subset of brain cells that sense circulating sugar levels, or were missing the protein entirely.

The study’s senior author Sabrina Diano, a professor in the Departments of Obstetrics, Gynecology and Reproductive Sciences, Neuroscience, and Comparative Medicine at the Yale School of Medicine, said, “We found that when sugar increases in the body, mitochondria in subsets of brain neurons rapidly change their shape and their function is altered.” She went on to explain that while the fact that these changes took place in response to glucose was not surprising, the fact that these seemingly small changes had such a powerful effect on circulating glucose by affecting the function of peripheral tissues was quite unexpected. Diano and her team want to further analyze whether these mitochondrial changes in the brain are related to the onset and propagation of type 2 diabetes.